Ceramic oxide material having a perovskite structure with a general formula of ABO3, in which A and B are two cations of very different sizes, is commonly used in solid oxide fuel cells (SOFCs) due to good thermal stability, mechanical strength, and conductivity thereof. Specifically, GdCoO3-based ceramic oxide material has superior thermal stability and is a mixed ionic-electronic conductor, and thus is promisingly used as a cathode material for a solid oxide fuel cell.
Solid oxide fuel cells are conventionally operated at a relatively high temperature, for example, from 800° C. to 1000° C., due to the relatively high reaction activation energy of solid oxide materials used therein. It is desirable in the art to provide a ceramic oxide material of the perovskite structure which still has satisfactory electrical conductivity at a relatively low temperature, for example, from 500° C. to 800° C.
An article entitled “Gd1-xSrxCoO3 for the electrode of solid oxide fuel cells” by Y. Takeda et al. in Solid State Ionic 86-88 (1996) 1187-1190 discloses a study of a system of Gd1-xSrxCoO3 for electrical conductivity, cathodic polarization and reactivity.
Another article entitled “Effect of strontium and barium doping on the magnetic state and electrical conductivity of GdCoO3” by N. B. Ivanova et al. in Physics of the Solid State, vol. 49, 2007, pp. 1498-1506 discloses a coordinated investigation of magnetic and electrical properties of polycrystalline cobalt oxide compounds GdCoO3, Gd0.9Ba0.1CoO3, and Gd0.9Sr0.1CoO3.